This old story is about an old man and a clever monkey. Aesop, a Greek writer first told t

he story many years ago. This monkey belonged to the old man. The old man likes the garden very much. When birds came to the garden the monkey chased them away. He also helped the old man in many other ways. The old man often fell asleep during the day in his chair. Then the monkey sat at the old man's side and chased the flies away from the old man's face.

One hot afternoon in the summer, the old man was asleep in his chair. A fly came and sat on the end of the old man's face. The monkey chased it away. Soon the fly came back and sat on the old man's face again. The monkey chased it away. This continued about four or five times. The monkey at last became very angry. He jumped up, ran to the garden, and picked up a large stone. The next time when the fly sat on the old man's face, the monkey hit it hard with the stone. He killed the fly. But unfortunately he broke the old man's face.

When birds came to the garden, the monkey chased them away. The verb "chased" means__________.

A．drive out

B．get rid of

C．catch up with

D．keep up with